The present invention relates to a closure cap and a sealed package and more particularly to an improved closure cap having a metallic innerseal where the innerseal is initially attached to the container rim by an induction sealing operation.
The closure cap of the present invention is of the type where a hermetic seal is obtained by including a membrane or foil innerseal within the cap shell and where the innerseal is attached to the container rim to form the hermetic seal. The preferred attachment is made by using heat sensitive adhesive on the innerseal and by heating the innerseal using radio frequency induction heating while downward pressure is applied to the closure cap. Where the container is glass, the foil engaging surface of the container may have a bond enhancing coating such as a relatively thick tin oxide coating or other applied coating.
Packages are well known which utilize one form or another of an innerseal to provide an hermetic seal. In the sealing operations utilizing these innerseals, the innerseals are applied to the container along with the closure cap and the innerseal is fastened to the container utilizing adhesives. When the closure cap is removed, the innerseal remains on the container until it is removed or punctured by the package user.
The closure cap of the present invention differs from these prior closure caps by being particularly adapted for use with an aluminum or other current conducting innerseal and more particularly where the innerseal attachment is made using radio frequency induction heating. Additionally, a tin oxide or other coating is used on a glass container finish for improving the adhesion of the innerseal and also for contributing to the efficiency of the R.F. induction sealing operation. No coating is required where the cap is used on plastic containers. The closure cap facilitates both the initial induction sealing and also provides a substantially airtight reseal after the package has been opened and when the consumer wishes to reseal it.
These improved results are provided by the combination of a molded plastic cap having a container gripping or strapping action at the corner of the cap and additionally by having a relatively thin and somewhat flexible cap top and skirt for facilitating the induction heating of the innerseal. The container has a cooperating wide sealing area on its rim and also a rim of minimal wall thickness.
Accordingly, an object of the present invention is to provide improved induction sealed package.
Another object of the present invention is to provide an improved closure.
Another object of the present invention is to provide an improved plastic or glass package sealed with a metallic innerseal.
Another object of the present invention is to provide an improved closure for sealing a tin oxide coated container with an induction heated metallic foil.
Another object of the present invention is to provide an improved sealed package utilizing a combination of a tin oxide coated container with a molded plastic closure having a metallic innerseal.
Other and further objects of the present invention will by obvious upon an understanding of the illustrative embodiments about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.